Answer this question truthfully
### Question: What causes Vertebrobasilar insufficiency?
### Response: The vertebrobasilar system is also called the back (posterior) circulation of the brain. Three main blood vessels provide blood flow to the back of the brain:
One basilar artery Two vertebral arteries
The back of the brain contains structures that are crucial for keeping a person alive. For instance, the brainstem controls breathing and swallowing, among other things. Parts of the brain help with vision (occipital lobes) and movement coordination (cerebellus) are also located in the back of the brain.
Many different conditions may cause blood flow in the back part of the brain to be reduced or stopped. The most common cause is a stroke due to hardening of the arteries (atherosclerosis).
Vertebrobasilar vascular disorders may also be caused if a tear (dissection) in an artery wall leads to the release of a clot that blocks blood flow. Dissection can be caused by clogged arteries, conditions such as fibromuscular dysplasia, or injuries such a car accident. It may even be caused by manipulations of the neck by a chiropractor, or during massage. However, most of the time, no apparent cause of dissection can be identified. When vertebrobasilar disease is present in a younger person, dissection of one of the arteries is often the cause.
Other less common causes of vertebrobasilar vascular disorders include connective tissue diseases and vasculitis.